CVE-2026-85571 in Tutor LMS Plugin
Summary
by MITRE • 10/10/2026
The Tutor LMS WordPress plugin before 4.1.1 does not verify that the posts named in its course content ordering requests belong to a course the requester manages, allowing users with instructor level access to reassign the parent of any post on the site, taking other instructors' course content into their own courses and making arbitrary published content unreachable.
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Analysis
by VulDB Data Team • 10/10/2026
The vulnerability identified in Tutor LMS versions prior to 4.1.1 represents a critical failure in server-side authorization logic within a widely used WordPress learning management system plugin. This flaw stems from an insufficient verification of object ownership during the processing of course content ordering requests. Specifically, when an instructor attempts to reorder or reorganize posts associated with their courses, the application fails to validate that the target post belongs to a course managed by the authenticated user initiating the request. Instead of enforcing strict access controls based on the relationship between the user and the specific educational resource being modified, the system accepts any valid authentication token from an instructor-level account and applies the requested structural changes globally across the site's content hierarchy. This architectural oversight allows for unauthorized manipulation of post metadata, fundamentally breaking the isolation boundaries intended to separate different instructors' course materials within a multi-instructor environment.
From a technical perspective, this issue is classified as Broken Access Control, aligning with CWE-269 in the Common Weakness Enumeration database. The core mechanism involves an insecure direct object reference pattern where the application relies on client-supplied identifiers for post IDs without cross-referencing them against the current user's authorized course list stored in the backend database. By exploiting this logic gap, a malicious actor with instructor privileges can execute arbitrary function calls that alter the parent-child relationships of posts across the entire WordPress installation. This capability extends beyond simple reordering; it enables the attacker to assign any published post on the site as a child of their own courses or remove such associations entirely. The vulnerability does not require elevated administrative rights, which significantly lowers the barrier for exploitation and increases the potential attack surface within multi-user educational platforms where multiple instructors operate independently.
The operational impact of this vulnerability is severe, affecting both data integrity and availability. An attacker can effectively hijack course content by reassigning posts from other instructors to their own courses, leading to intellectual property theft and confusion among students who may encounter mixed or incorrect learning materials. Furthermore, the ability to make arbitrary published content unreachable poses a significant risk to service continuity. By altering post parents in ways that disrupt navigation structures or remove them from expected course modules, attackers can render legitimate educational resources inaccessible to enrolled users without necessarily deleting the underlying data. This results in a denial of service for specific learning paths and undermines trust in the platform's reliability. Additionally, such unauthorized modifications could be used as a stepping stone for further attacks, potentially leading to privilege escalation if subsequent vulnerabilities exist that rely on trusted post relationships or metadata states.
Mitigation strategies must prioritize immediate patching alongside temporary administrative controls. The primary remediation is to upgrade Tutor LMS to version 4.1.1 or later, where the developers have implemented proper authorization checks to ensure users can only modify posts associated with courses they own or manage. In environments where upgrading is not immediately feasible, administrators should restrict instructor-level access by auditing user roles and removing unnecessary capabilities that allow for broad post manipulation. Implementing a Web Application Firewall (WAF) rule set designed to detect anomalous patterns in course content ordering requests may also provide partial protection against automated exploitation attempts. Regular security audits focusing on role-based access control implementations are essential to prevent similar logic flaws from persisting in custom plugins or themes integrated with the learning management system.
This incident highlights the importance of rigorous input validation and authorization checks in multi-tenant applications, even when those tenants share a single database instance. The vulnerability aligns with MITRE ATT&CK technique T1078, Valid Accounts, as it leverages legitimate instructor credentials to perform unauthorized actions that compromise confidentiality and availability. Security teams should treat such logic flaws with the same urgency as traditional injection or execution vulnerabilities because they often bypass perimeter defenses by operating within authenticated sessions. Continuous monitoring of administrative logs for unusual post reassignment activities can aid in early detection of exploitation attempts, ensuring rapid response before significant damage to course content integrity occurs.